1. Field
The following description relates to a piezoelectric oscillator and method of making the same.
2. Description of Related Art
A piezoelectric oscillator is a device generating oscillations having a certain frequency through a piezoelectric material oscillating due to a piezoelectric phenomenon occurring when a voltage is applied to the piezoelectric oscillator. Since the piezoelectric oscillator has a stable oscillation frequency, such a device has been used in several core components providing a reference signal value as well as in an oscillation circuit of a computer or a communications device.
A piezoelectric oscillator includes a crystal, an oscillation substrate using the crystal as a base material and an electrode disposed on the oscillation substrate, wherein the oscillation substrate may have various shapes depending on required physical properties.
When a piezoelectric oscillator is formed so that a thickness of the oscillation substrate is gradually reduced from a central portion thereof toward end portions thereof and is in a thickness shear oscillation mode, a damping amount of oscillation displacement in the end portion is increased. Thus, an effect in which oscillation energy is trapped in the central portion of the piezoelectric oscillator may be improved, and frequency characteristics such as a CI value and a Q value, may also be improved. An example of a shape of the piezoelectric oscillator that may accomplish an oscillation energy trapping effect may include a convex shape in which a convex curved surface is formed as a main surface, a bevel shape in which a space between a flat and thick central portion and an edge of an end portion is formed as an inclined surface, and a mesa, or stepped, shape in which a central portion is flat and a surrounding portion of the central portion is thin.